i use HB but to make it look darker i use B´s like B2 or B4 ,its also a matter of how used you are to use the pencil you can darken it with ordinary pencils if you have enough practice and know what areas should be darker or lighter

first of all thanks for the message!I already know that but I wanted to know if you used another way to make that. I just saw another drawing that you did and that you used a white pen/other material (that i want to know which one) to sign your drawing, that I really like because it looks awesome! Can you tell me which one? Thanks once again!